Photothermal and Photodynamic Synergistic Effect of the MXene/SnS2 Heterojunction Endows the Poly(l-lactic acid) Scaffold with Antibacterial Activity

Abstract

Bacterial infection is a severe challenge faced by artificial bone transplantation, which might cause delayed bone healing or even transplant failure. Photodynamic therapy (PDT) has garnered widespread attention as a treatment for infections due to its noninvasiveness, few side effects, and high spatiotemporal selectivity. Nevertheless, owing to the bacterial membrane obstacle, it is difficult for exogenous reactive oxygen species (ROS) to penetrate into bacteria, which leads to an unsatisfactory antibacterial effect. Herein, a heterojunction of Ti₂C₃ nanosheets/tin disulfide (MXene/SnS₂) is designed, which integrates photothermal and photodynamic properties. Then, MXene/SnS₂ was incorporated into a poly-l-lactic acid powder (PLLA) matrix to fabricate an artificial bone scaffold with selective laser sintering (SLS) technology. Under near-infrared laser irradiation, SnS₂ can strengthen the near-infrared light absorption of MXene to generate local hyperthermia, thus enhancing bacterial membrane permeability. Meanwhile, MXene/SnS₂ enhances charge transfer and inhibits electron–hole pair separation, thereby generating more ROS that can penetrate the bacterial interior. The results indicated that this antibacterial strategy has effective antibacterial activity, and the antibacterial rate reached over 90%. Overall, this research presents an attractive antibacterial strategy for implant-related infection.